Surgical interventions (microfracture, drilling, mosaicplasty, and allograft transplantation) for treating isolated cartilage defects of the knee in adults

Multilayered Cryogel Enriched with Exosomes Regenerates and Maintains Cartilage Architecture and Phenotype in Goat Osteochondral Injuries

Treatment of critical-size osteochondral (OC) injuries at load-bearing sites has remained a major clinical challenge in orthopedic surgery. This is due to the anisotropic characteristics of OC tissue and the stratified structure of the cartilage. Here, we developed a multilayered OC scaffold by employing cryogelation technology. Gelatin, chitosan, and chondroitin sulfate were utilized for designing three distinct, 2425 ± 120 μm thick layers of cartilage having different alignments, while nanohydroxyapatite and gelatin were used for the subchondral bone layer. Exosomes derived from articular chondrocytes in the range of 60-110 nm were used to promote chondrogenesis. The biocompatibility and cartilage formation potential of the scaffold and exosomes were initially evaluated in rat OC defects. The application of exosome-loaded scaffolds was then investigated in a critical-size OC injury (8 × 10 mm) created in the goat knee. Artificial synovial fluid was designed and utilized as a carrier for exosomes for a booster dose administered as an intra-articular injection. X-ray imaging and micro-CT analysis revealed that the treatment resulted in improved subchondral bone regeneration. The defect region exhibited healthy hyaline cartilage formation, as detected by MRI imaging. Moreover, histological examination revealed that the treatment group showed augmented cell proliferation, matrix deposition, secretion of proteoglycans, and the formation of stratified hyaline cartilage over a long-term (6 and 12 months), whereas the control group demonstrated the formation of fibrocartilage. Treatment-induced upregulation of collagen II, aggrecan, and SOX 9 genes (∼10 fold) further provided evidence that the cartilage phenotype was well preserved. Hence, the proposed treatment has significant translational potential for treating adverse OC clinical injuries.

Adipose-derived regenerative therapies for the treatment of knee osteoarthritis

Knee osteoarthritis is a degenerative condition with a significant disease burden and no disease-modifying therapy. Definitive treatment ultimately requires joint replacement. Therapies capable of regenerating cartilage could significantly reduce financial and clinical costs. The regenerative potential of mesenchymal stromal cells (MSCs) has been extensively studied in the context of knee osteoarthritis. This has yielded promising results in human studies, and is likely a product of immunomodulatory and chondroprotective biomolecules produced by MSCs in response to inflammation. Adipose-derived MSCs (ASCs) are becoming increasingly popular owing to their relative ease of isolation and high proliferative capacity. Stromal vascular fraction (SVF) and micro-fragmented adipose tissue (MFAT) are produced by the enzymatic and mechanical disruption of adipose tissue, respectively. This avoids expansion of isolated ASCs ex vivo and their composition of heterogeneous cell populations, including immune cells, may potentiate the reparative function of ASCs. In this editorial, we comment on a multicenter randomized trial regarding the efficacy of MFAT in treating knee osteoarthritis. We discuss the study's findings in the context of emerging evidence regarding adipose-derived regenerative therapies. An underlying mechanism of action of ASCs is proposed while drawing important distinctions between the properties of isolated ASCs, SVF, and MFAT.

Surgical Treatment of Focal Chondral Lesions of the Knee in the Military Population: Current and Future Therapies

INTRODUCTION

Chondral and osteochondral defects of the knee are common injuries in the military population that have a significant impact on readiness. Definitive treatment of these injuries is challenging since cartilage has a limited capacity for self-repair and regeneration. Management is particularly challenging in military patients who maintain a higher level of activity similar to athletes. Existing surgical techniques have variable results and often long recovery times, sparking the development of several new innovative technologies to return service members back to duty more quickly and effectively after cartilage injury. The purpose of this article is to review the current and future surgical treatments for chondral and osteochondral knee lesions and their relevance in managing these injuries in the military.

METHODS

In this review article, we describe the current treatments for chondral and osteochondral defects of the knee, reporting on outcomes in military populations. We explore emerging treatment modalities for cartilage defects, reporting innovations, stage of research, and current data. Published results of each treatment option in military populations are reviewed throughout the article.

RESULTS

This review includes 12 treatments for chondral lesions. Of these therapies, four are considered synthetic and the remaining are considered regenerative solutions. Regenerative therapies tend to perform better in younger, healthier populations with robust healing capacity. Success of treatment depends on lesions and patient characteristics. Nearly all modalities currently available in the USA were successful in improving patients from presurgical function in the short (<6 months) term, but the long-term efficacy is still challenged. Upcoming technologies show promising results in clinical and animal studies that may provide alternative options desirable for the military population.

CONCLUSIONS

The current treatment options for cartilage lesions are not entirely satisfactory, usually with long recovery times and mixed results. An ideal therapy would be a single procedure that possesses the ability to enable a quick return to activity and duty, alleviate pain, provide long-term durability, and disrupt the progression of osteoarthritis. Evolving technologies for cartilage lesions are expanding beyond currently available techniques that may revolutionize the future of cartilage repair.

PUD@HA/PEEK Scaffold Induces Subchondral Bone Regeneration to Repair Osteochondral Defect in Rabbits

Osteochondral defects (OCDs) pose a significant challenge in clinical practice, and recent advancements in their repair indicate that satisfying subchondral bone repair may be critical for this. Herein, a series of hydroxyapatite/poly(ether ether ketone) (HA/PEEK) scaffolds were fabricated with varying mass percentages (0, 20, 30, and 40%) to induce subchondral bone regeneration. Subsequently, an optimal scaffold with 40% HA/PEEK was selected to establish osteochondral scaffolds with poly(ether urethane) urea-Danshensu (PUD) for repairing the OCD. The material characteristics of HA/PEEK and PUD were investigated using scanning electron microscopy, tensile, swelling, and fatigue tests, and cytological experiments. The effects of serial HA/PEEK scaffolds on subchondral bone repair were then assessed by using microcomputed tomography, hard tissue slicing, and histological staining. Furthermore, the optimal 40% HA/PEEK scaffold was used to develop osteochondral scaffolds with PUD to observe the effect on the OCD repair. HA/PEEK materials exhibited an even HA distribution in PEEK. However, when composited with HA, PEEK exhibited inferior mechanical strength. 40%HA/PEEK scaffolds showed an optimum effect on in vivo subchondral bone repair. Cartilage regeneration on 40%HA/PEEK scaffolds was pronounced. After PUD was introduced onto the HA/PEEK, the PUD@40%HA/PEEK scaffold produced the expected effect on the repair of the OCD in rabbits. Therefore, achieving satisfactory subchondral bone repair can benefit surficial cartilage repair. The PUD@40%HA/PEEK scaffold could induce subchondral bone regeneration to repair the OCD in rabbits and could provide a novel approach for the repair of the OCD in clinical practice.

Drug/bioactive eluting chitosan composite foams for osteochondral tissue engineering

Joint defects associated with a variety of etiologies often extend deep into the subchondral bone leading to functional impairment and joint immobility, and it is a very challenging task to regenerate the bone-cartilage interface offering significant opportunities for biomaterial-based interventions to improve the quality of life of patients. Herein drug-/bioactive-loaded porous tissue scaffolds incorporating nano-hydroxyapatite (nHAp), chitosan (CS) and either hydroxypropyl methylcellulose (HPMC) or Bombyx mori silk fibroin (SF) are fabricated through freeze drying method as subchondral bone substitute. A combination of spectroscopy and microscopy (Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX), and X-ray fluorescence (XRF) were used to analyze the structure of the porous biomaterials. The compressive mechanical properties of these scaffolds are biomimetic of cancellous bone tissues and capable of releasing drugs/bioactives (exemplified with triamcinolone acetonide, TA, or transforming growth factor-β1, TGF-β1, respectively) over a period of days. Mouse preosteoblast MC3T3-E1 cells were observed to adhere and proliferate on the tissue scaffolds as confirmed by the cell attachment, live-dead assay and alamarBlue™ assay. Interestingly, RT-qPCR analysis showed that the TA downregulated inflammatory biomarkers and upregulated the bone-specific biomarkers, suggesting such tissue scaffolds have long-term potential for clinical application.

Consensus Guidelines on Interventional Therapies for Knee Pain (STEP Guidelines) from the American Society of Pain and Neuroscience

Knee pain is second only to the back as the most commonly reported area of pain in the human body. With an overall prevalence of 46.2%, its impact on disability, lost productivity, and cost on healthcare cannot be overlooked. Due to the pervasiveness of knee pain in the general population, there are no shortages of treatment options available for addressing the symptoms. Ranging from physical therapy and pharmacologic agents to interventional pain procedures to surgical options, practitioners have a wide array of options to choose from - unfortunately, there is no consensus on which treatments are "better" and when they should be offered in comparison to others. While it is generally accepted that less invasive treatments should be offered before more invasive ones, there is a lack of agreement on the order in which the less invasive are to be presented. In an effort to standardize the treatment of this extremely prevalent pathology, the authors present an all-encompassing set of guidelines on the treatment of knee pain based on an extensive literature search and data grading for each of the available alternative that will allow practitioners the ability to compare and contrast each option.

Human Osteochondral Explants as an Ex Vivo Model of Osteoarthritis for the Assessment of a Novel Class of Orthobiologics

Osteoarthritis (OA) is a highly prevalent joint disease still lacking effective treatments. Its multifactorial etiology hampers the development of relevant preclinical models to evaluate innovative therapeutic solutions. In the last decade, the potential of Mesenchymal Stem Cell (MSC) secretome, or conditioned medium (CM), has emerged as an alternative to cell therapy. Here, we investigated the effects of the CM from adipose MSCs (ASCs), accounting for both soluble factors and extracellular vesicles, on human osteochondral explants. Biopsies, isolated from total knee replacement surgery, were cultured without additional treatment or with the CM from 10⁶ ASCs, both in the absence and in the presence of 10 ng/mL TNFα. Tissue viability and several OA-related hallmarks were monitored at 1, 3 and 6 days. Specimen viability was maintained over culture. After 3 days, TNFα induced the enhancement of matrix metalloproteinase activity and glycosaminoglycan release, both efficiently counteracted by CM. The screening of inflammatory lipids, proteases and cytokines outlined interesting modulations, driving the attention to new players in the OA process. Here, we confirmed the promising beneficial action of ASC secretome in the OA context and profiled several bioactive factors involved in its progression, in the perspective of accelerating an answer to its unmet clinical needs.

The Use of Autologous Chondrocyte and Mesenchymal Stem Cell Implants for the Treatment of Focal Chondral Defects in Human Knee Joints-A Systematic Review and Meta-Analysis

Focal chondral defects of the knee occur commonly in the young, active population due to trauma. Damage can insidiously spread and lead to osteoarthritis with significant functional and socioeconomic consequences. Implants consisting of autologous chondrocytes or mesenchymal stem cells (MSC) seeded onto scaffolds have been suggested as promising therapies to restore these defects. However, the degree of integration between the implant and native cartilage still requires optimization. A PRISMA systematic review and meta-analysis was conducted using five databases (PubMed, MEDLINE, EMBASE, Web of Science, CINAHL) to identify studies that used autologous chondrocyte implants (ACI) or MSC implant therapies to repair chondral defects of the tibiofemoral joint. Data on the integration of the implant-cartilage interface, as well as outcomes of clinical scoring systems, were extracted. Most eligible studies investigated the use of ACI only. Our meta-analysis showed that, across a total of 200 patients, 64% (95% CI (51%, 75%)) achieved complete integration with native cartilage. In addition, a pooled improvement in the mean MOCART integration score was observed during post-operative follow-up (standardized mean difference: 1.16; 95% CI (0.07, 2.24), p = 0.04). All studies showed an improvement in the clinical scores. The use of a collagen-based scaffold was associated with better integration and clinical outcomes. This review demonstrated that cell-seeded scaffolds can achieve good quality integration in most patients, which improves over time and is associated with clinical improvements. A greater number of studies comparing these techniques to traditional cartilage repair methods, with more inclusion of MSC-seeded scaffolds, should allow for a standardized approach to cartilage regeneration to develop.

Scaffold-Based Tissue Engineering Strategies for Osteochondral Repair

Over centuries, several advances have been made in osteochondral (OC) tissue engineering to regenerate more biomimetic tissue. As an essential component of tissue engineering, scaffolds provide structural and functional support for cell growth and differentiation. Numerous scaffold types, such as porous, hydrogel, fibrous, microsphere, metal, composite and decellularized matrix, have been reported and evaluated for OC tissue regeneration in vitro and in vivo, with respective advantages and disadvantages. Unfortunately, due to the inherent complexity of organizational structure and the objective limitations of manufacturing technologies and biomaterials, we have not yet achieved stable and satisfactory effects of OC defects repair. In this review, we summarize the complicated gradients of natural OC tissue and then discuss various osteochondral tissue engineering strategies, focusing on scaffold design with abundant cell resources, material types, fabrication techniques and functional properties.

[Surgical treatment of focal cartilage defects in the knee : Indications, techniques, modifications and results]

The treatment strategies for focal cartilage damage in the knee are multifarious. For established procedures, such as microfracturing (MFX), autologous matrix-induced chondrogenesis (AMIC), osteochondral transplantation (OCT) and autologous chondrocyte transplantation (ACT), well-founded, partly comparative long-term studies and overlapping size-dependent differential indications are available. Innovative cell sources, the utilization of biological scaffolds as well as biologic agents and various combinations, have recently become the focus of scientific attention; however, high regulatory demands are restricting their use in Germany. The success of every procedure is dependent on the appropriate indications, the treatment of comorbidities, such as axis deviations or ligamentous instability, the surgeon's experience and an adequate follow-up treatment.

Cost-effectiveness analysis of arthroscopic injection of a bioadhesive hydrogel implant in conjunction with microfracture for the treatment of focal chondral defects of the knee - an Australian perspective

AIM

JointRep is a bioadhesive hydrogel arthroscopically injected to facilitate cartilage regeneration. The cost-effectiveness of JointRep with microfracture surgery compared to microfracture alone was evaluated from the Australian healthcare system perspective, in patients with symptomatic focal chondral defects (Outerbridge Grade 3 or 4) of the knee who had failed conservative treatment and were indicated for surgery.

MATERIALS AND METHODS

A de novo Markov model comprising two health states- 'Alive' and 'Dead' was developed. Model transition probability was based on the general population mortality rates. Clinical outcomes were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, a validated patient-reported tool measuring pain, stiffness, and physical function. The utility was derived by mapping WOMAC scores to EQ-5D scores using a published algorithm. Cost inputs were based on published Australian costs from AR-DRGs, Medicare Benefits Schedule, and Prostheses List. Model outcomes included costs, Quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER). Base-case analysis was conducted for a time horizon of 3 years and a cycle length of 1 year. Cost and health outcomes were discounted at 5% per annum. Sensitivity and scenario analyses were also conducted.

RESULTS

Total QALYs were estimated to be higher for JointRep with microfracture surgery (2.61) compared to microfracture surgery alone (1.66), an incremental gain of 0.95 QALY. JointRep with microfracture surgery was associated with an incremental cost of $6,022 compared to microfracture surgery alone, thus leading to an ICER of $6,328. Results were substantially robust to varying parameters in the sensitivity analyses conducted, alternative model settings and assumptions in scenario analyses.

LIMITATIONS

The clinical inputs used in the model were based on data from short duration, non-randomized, post-market clinical trial.

CONCLUSIONS

JointRep with microfracture surgery is a cost-effective treatment option compared to microfracture alone from the Australian health care system perspective.

Resorbable Pins to Enhance Scaffold Retention in a Porcine Chondral Defect Model

OBJECTIVE

Cartilage repair strategies have seen improvement in recent years, especially with the use of scaffolds that serve as a template for cartilage formation. However, current fixation strategies are inconsistent with regards to retention, may be technically challenging, or may damage adjacent tissues or the implant itself. Therefore, the goal of this study was to evaluate the retention and repair potential of cartilage scaffolds fixed with an easy-to-implement bioresorbable pin.

DESIGN

Electrospun hyaluronic acid scaffolds were implanted into trochlear groove defects in 3 juvenile and 3 adult pigs to evaluate short-term retention (2 weeks; pin fixation vs. press-fit and fibrin fixation) and long-term repair (8 months; scaffold vs. microfracture), respectively.

RESULTS

For the retention study, press-fit and fibrin fixation resulted in short-term scaffold dislodgment (n = 2 each), whereas pin fixation retained all scaffolds that were implanted (n = 6). Pin fixation did not cause any damage to the opposing patellar surface, and only minor changes in the subchondral bone were observed. For long-term repair, no differences were observed between microfracture and scaffold groups, in terms of second-look arthroscopy and indentation testing. On closer visualization with micro computed tomography and histology, a high degree of variability was observed between animals with regard to subchondral bone changes and cartilage repair quality, yet each Scaffold repair displayed similar properties to its matched microfracture control.

CONCLUSIONS

In this study, pin fixation did not cause adverse events in either the short- or the long-term relative to controls, indicating that pin fixation successfully retained scaffolds within defects without inhibiting repair.

3D Printed Multiphasic Scaffolds for Osteochondral Repair: Challenges and Opportunities

Osteochondral (OC) defects are debilitating joint injuries characterized by the loss of full thickness articular cartilage along with the underlying calcified cartilage through to the subchondral bone. While current surgical treatments can provide some relief from pain, none can fully repair all the components of the OC unit and restore its native function. Engineering OC tissue is challenging due to the presence of the three distinct tissue regions. Recent advances in additive manufacturing provide unprecedented control over the internal microstructure of bioscaffolds, the patterning of growth factors and the encapsulation of potentially regenerative cells. These developments are ushering in a new paradigm of 'multiphasic' scaffold designs in which the optimal micro-environment for each tissue region is individually crafted. Although the adoption of these techniques provides new opportunities in OC research, it also introduces challenges, such as creating tissue interfaces, integrating multiple fabrication techniques and co-culturing different cells within the same construct. This review captures the considerations and capabilities in developing 3D printed OC scaffolds, including materials, fabrication techniques, mechanical function, biological components and design.

[Surgical treatment of focal cartilage defects in the knee : Indications, techniques, modifications and results]

The treatment strategies for focal cartilage damage in the knee are multifarious. For established procedures, such as microfracturing (MFX), autologous matrix-induced chondrogenesis (AMIC), osteochondral transplantation (OCT) and autologous chondrocyte transplantation (ACT), well-founded, partly comparative long-term studies and overlapping size-dependent differential indications are available. Innovative cell sources, the utilization of biological scaffolds as well as biologic agents and various combinations, have recently become the focus of scientific attention; however, high regulatory demands are restricting their use in Germany. The success of every procedure is dependent on the appropriate indications, the treatment of comorbidities, such as axis deviations or ligamentous instability, the surgeon's experience and an adequate follow-up treatment.

Back Propagation Neural Network-Based Ultrasound Image for Diagnosis of Cartilage Lesions in Knee Osteoarthritis

Objective

To explore the application value of ultrasound image based on back propagation (BP) neural network algorithm in knee osteoarthritis (KOA) and evaluate the application effect and value of ultrasound image technology based on the BP neural network in the diagnosis of knee osteoarthritis cartilage lesions, 98 patients who were admitted to our hospital were diagnosed with KOA and had undergone arthroscopic soft tissue examinations were randomly selected. According to whether image processing was performed, the ultrasound images of all patients were divided into two groups. The control group was image before processing, and the experimental group was image after processing optimization. The consistency of the inspection results of the ultrasound images before and after the processing with the arthroscopy results was compared. The results showed that the staging accuracy of the control group was 68.3% and that of the experimental group was 76.9%. The accuracy of staging cartilage degeneration of the experimental group was higher than that of the control group, and the difference was not remarkable (P > 0.05). The kappa coefficient of the experimental group was 0.61, and that of the control group was 0.40. The kappa coefficient of the experimental group was higher than that of the control group, and the difference was significant (P < 0.05).

Conclusion

The inspection effect of the ultrasound image processed by the BP neural network was superior to that of the conventional ultrasound image. It reflected the good adoption prospect of neural networks in image processing.

Cartilage Tissue Engineering by Extrusion Bioprinting: Process Analysis, Risk Evaluation, and Mitigation Strategies

Extrusion bioprinting is considered promising in cartilage tissue engineering since it allows the fabrication of complex, customized, and living constructs potentially suitable for clinical applications. However, clinical translation is often complicated by the variability and unknown/unsolved issues related to this technology. The aim of this study was to perform a risk analysis on a research process, consisting in the bioprinting of a stem cell-laden collagen bioink to fabricate constructs with cartilage-like properties. The method utilized was the Failure Mode and Effect Analysis/Failure Mode and Effect Criticality Analysis (FMEA/FMECA) which foresees a mapping of the process to proactively identify related risks and the mitigation actions. This proactive risk analysis allowed the identification of forty-seven possible failure modes, deriving from seventy-one potential causes. Twenty-four failure modes displayed a high-risk level according to the selected evaluation criteria and threshold (RPN > 100). The results highlighted that the main process risks are a relatively low fidelity of the fabricated structures, unsuitable parameters/material properties, the death of encapsulated cells due to the shear stress generated along the nozzle by mechanical extrusion, and possible biological contamination phenomena. The main mitigation actions involved personnel training and the implementation of dedicated procedures, system calibration, printing conditions check, and, most importantly, a thorough knowledge of selected biomaterial and cell properties that could be built either through the provided data/scientific literature or their preliminary assessment through dedicated experimental optimization phase. To conclude, highlighting issues in the early research phase and putting in place all the required actions to mitigate risks will make easier to develop a standardized process to be quickly translated to clinical use.

Human Salivary Histatin-1-Functionalized Gelatin Methacrylate Hydrogels Promote the Regeneration of Cartilage and Subchondral Bone in Temporomandibular Joints

The avascular structure and lack of regenerative cells make the repair of osteochondral defects in the temporomandibular joint (TMJ) highly challenging in the clinic. To provide a viable treatment option, we developed a methacrylated gelatin (Gel-MA) hydrogel functionalized with human salivary histatin-1 (Hst1). Gel-MA is highly biocompatible, biodegradable, and cost-effective. Hst1 is capable of activating a series of cell activities, such as adhesion, migration, differentiation, and angiogenesis. To evaluate the efficacy of Hst1/Gel-MA, critical-size osteochondral defects (3 mm in diameter and 3 mm in depth) of TMJ in New Zealand white rabbits were surgically created and randomly assigned to one of the three treatment groups: (1) control (no filling material); (2) Gel-MA hydrogel; (3) Hst1/Gel-MA hydrogel. Samples were retrieved 1, 2, and 4 weeks post-surgery and subjected to gross examination and a series of histomorphometric and immunological analyses. In comparison with the control and Gel-MA alone groups, Hst1/Gel-MA hydrogel was associated with significantly higher International Cartilage Repair Society score, modified O’Driscoll score, area percentages of newly formed bone, cartilage, collagen fiber, and glycosaminoglycan, and expression of collagen II and aggrecan. In conclusion, Hst1/Gel-MA hydrogels significantly enhance bone and cartilage regeneration, thus bearing promising application potential for repairing osteochondral defects.

Stabilization of Damaged Articular Cartilage with Hydrogel-Mediated Reinforcement and Sealing

Cartilage injuries and subsequent tissue deterioration impact millions of patients. Since the regeneration of functional hyaline cartilage remains elusive, methods to stabilize the remaining tissue, and prevent further deterioration, would be of significant clinical utility and prolong joint function. Finite element modeling shows that fortification of the degenerate cartilage (Reinforcement) and reestablishment of a superficial zone (Sealing) are both required to restore fluid pressurization within the tissue and restrict fluid flow and matrix loss from the defect surface. Here, a hyaluronic acid (HA) hydrogel system is designed to both interdigitate with and promote the sealing of the degenerated cartilage. Interdigitating fortification restores both bulk and local pericellular tissue mechanics, reestablishing the homeostatic mechanotransduction of endogenous chondrocytes within the tissue. This HA therapy is further functionalized to present chemo mechanical cues that improve the attachment and direct the response of mesenchymal stem/stromal cells at the defect site, guiding localized extracellular matrix deposition to "seal" the defect. Together, these results support the therapeutic potential, across cell and tissue length scales, of an innovative hydrogel therapy for the treatment of damaged cartilage.

Wide Variation in Methodology in Level I and II Studies on Cartilage Repair: A Systematic Review of Available Clinical Trials Comparing Patient Demographics, Treatment Means, and Outcomes Reporting

BACKGROUND

The management of complex cartilage pathology in young, otherwise healthy patients can be difficult.

PURPOSE

To determine the nature of the design, endpoints chosen, and rate at which the endpoints were met in published studies and ongoing clinical trials that investigate cartilage repair and restoration procedures.

STUDY DESIGN

Systematic review.

METHODS

A systematic review of the publicly available level I/II literature and of the publicly listed clinical trials regarding cartilage repair and restoration procedures for the knee was conducted adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Seventeen published studies and 52 clinical trials were included. Within the 17 published studies, the most common procedure studied was microfracture (MFX) + augmentation (N = 5; 29.4%) and the most common comparison/control group was MFX (N = 10; 58.8%). In total, 13 different cartilage procedure groups were evaluated. For published studies, the most common patient-reported outcome (PRO) measures assessed is the Knee Injury and Osteoarthritis Outcome Score (KOOS) and Visual Analog Scale-Pain (VAS) (N = 10 studies, 58.8% each, respectively). Overall, there are 10 different PROs used among the included studies. Ten studies demonstrate superiority, 5 demonstrate noninferiority, and 2 demonstrate inferiority to the comparison or control groups. For the clinical trials included, the most common procedure studied is MFX + augmentation (N = 16; 30.8%). The most common PRO assessed is KOOS (N = 36 trials; 69.2%), and overall there are 24 different PROs used among the included studies.

CONCLUSIONS

Recently published studies and clinical trials evaluate a variety of cartilage repair and restoration strategies for the knee, most commonly MFX + augmentation, at various time points of outcome evaluation, with KOOS and VAS scores being used most commonly. MFX remains the most common comparison group for these therapeutic investigations. Most studies demonstrate superiority versus comparison or control groups. Understanding the nature of published and ongoing clinical trials will be helpful in the investigation of emerging technologies required to navigate the regulatory process while studying a relatively narrow population of patients.

A tri-component knee plug for the 3rd generation of autologous chondrocyte implantation

Here, we report a newly designed knee plug to be used in the 3rd generation of Autologous Chondrocyte Implantation (ACI) in order to heal the damaged knee cartilage. It is composed of three components: The first component (Bone Portion) is a 3D printed hard scaffold with large pores (~ 850 µm), made by hydroxyapatite and β-tricalcium phosphate to accommodate the bony parts underneath the knee cartilage. It is a cylinder with a diameter of 20 mm and height of 7.5 mm, with a slight dome shape on top. The plug also comprises a Cartilage Portion (component 2) which is a 3D printed gelatin/elastin/sodium-hyaluronate soft thick porous membrane with large pores to accommodate chondrocytes. Cartilage Portion is secured on top of the Bone Portion using mechanical interlocking by designing specific knobs in the 3D printed construct of the Cartilage Portion. The third component of the plug (Film) is a stitchable permeable membrane consisting of polycaprolactone (PCL) on top of the Cartilage Portion to facilitate sliding of the knee joint and to hold the entire plug in place while allowing nutrients delivery to the Cartilage Portion. The PCL Film is prepared using a combination of film casting and sacrificial material leaching with a pore size of 10 µm. It is surface modified to have specific affinity with the Cartilage Portion. The detailed design criteria and production process of this plug is presented in this report. Full in vitro analyses have been performed, which indicate the compatibility of the different components of the plug relative to their expected functions.

Collagenase treatment of cartilaginous matrix promotes fusion of adjacent cartilage

In articular cartilage-repair, grafts usually fuse unsatisfactorily with surrounding host cartilage. Enzymatic dissociation of cartilaginous matrix to free chondrocytes may benefit fusion. We tested such a hypothesis with human cartilage in vitro, and with porcine cartilage in vivo. Human articular cartilage was collected from knee surgeries, cut into disc-and-ring sets, and randomly distributed into three groups: disc-and-ring sets in Group 1 were left untreated; in Group 2 only discs, and in Group 3 both discs and rings were treated with enzyme. Each disc-and-ring reassembly was cultured in a perfusion system for 14 days; expression of cartilage marker proteins and genes was evaluated by immunohistochemistry and PCR. Porcine articular cartilage from knees was similarly fashioned into disc-and-ring combinations. Specimens were randomly distributed into a control group without further treatment, and an experimental group with both disc and ring treated with enzyme. Each disc-and-ring reassembly was transplanted into subcutaneous space of a nude mouse for 30 days, and retrieved to examine disc-ring interface. In in vitro study with human cartilage, a visible gap remained at disc-ring interfaces in Group 1, yet became indiscernible in Group 2 and 3. Marker genes, including type II collagen, aggrecan and Sox 9, were well expressed by chondrocytes in all specimens, indicating that chondrocytes’ phenotype retained regardless of enzymatic treatment. Similar results were found inin vivo study with porcine cartilage. Enzymatic dissociation of cartilaginous matrix promotes fusion of adjacent cartilage. The clinical relevance may be a novel method to facilitate integration of repaired cartilage in joints.

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Cartilage repair-patches fuse poorly to surrounding host cartilage.

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Collagenase treatment of adjacent cartilaginous tissues facilitates their fusion.

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Collagenase treatment of cartilage promotes chondrocyte proliferation and presentation.

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Collagenase treatment does not affect phenotypes of chondrocytes.

Compensation claims after knee cartilage surgery is rare. A registry-based study from Scandinavia from 2010 to 2015

BACKGROUND

Focal cartilage defects (FCDs) in the knee joint has a high prevalence. A broad range of treatment options exists for symptomatic patients. Knowledge of patient compensation claims following surgical treatment of FCDs is missing. The purpose of this study is to evaluate compensation claims filed to the Scandinavian registries for patient compensation following treatment of FCDs in the knee joint from 2010 to 2015 and identify possible areas of improvement.

METHODS

A cross-sectional study design was used to obtain all complaints following surgical treatment of FCDs from the Scandinavian registries from 2010 to 2015. Data such as age, gender, type of treatment, type of complaint, reason of verdict and amount of compensation were collected and systematically analyzed.

RESULTS

103 patients filed a compensation claim. 43 had received debridement (41.7%), 54 microfracture (MF) (52.4%), 3 mosaicplasty (2.9%) and 3 autologous chondrocyte implantation (ACI) (2.9%). Of the 103 claims, 36 were granted (35%). 21 following debridement (58.3%), 13 after MF (36.1%), 1 following mosaicplasty (2.8%) and 1 after ACI (2.8%). The most common reason for complaint was infection (22.1%), of which 89% were granted. The average compensation was €24.457 (range €209 - €458.943).

CONCLUSION

Compensation claims following surgical treatment of knee cartilage injuries in Scandinavia are rare. Establishing nationwide cartilage registries can add further knowledge on this troublesome disease.

Protocol for Harvest, Transport and Storage of Human Osteochondral Tissue

Objective  To elaborate a protocol for the harvest, transport, and preservation of human osteochondral tissue for use in tissue banks (TBs). Methods  Osteochondral fragments measuring 2 cm 3 of 5 corpse donors aged between 15 and 45 years old were analyzed. The samples were stored in cell preservation medium containing: human albumin, Iscove's and vancomycin preserved at 4°C. The concentration of proteoglycans in the extracellular medium was quantified by the use of Safranin-O, while tissue structural analysis was assessed by histological study with hematoxylin-eosin stained slides. The images obtained were analyzed according to the histological scores of Mankin and the score proposed by the OsteoArthritis Research Society International. The samples were analyzed with 0, 15, 30 and 45 days of preservation. Results  The osteochondral fragments studied showed a progressive decrease in proteoglycan concentration with increased preservation time. After 30 days of preservation, structural changes were identified with discontinuity of the cartilage surface layer. According to the results obtained by the Mankin score, there was a statistically significant difference between 15 and 30 days of tissue preservation. Conclusion  The protocol described defined knee transport immersed in Lactated Ringer at a controlled temperature of 10° C until its arrival at the TB. After processing, the preservation solution was composed of Iscove's serum-free cell culture medium supplemented with 10% human albumin and 100 μg/ml vancomycin. The tissue was preserved at a temperature of 4°C until the moment of transplantation characterizing the fresh preservation.

Microfracture for cartilage repair in the knee: a systematic review of the contemporary literature

PURPOSE

To systematically review and evaluate novel clinical data following microfracture treatment of knee articular cartilage defects.

METHODS

A systematic review was performed by searching PubMed, ScienceDirect, and Cochrane Library databases for clinical trials on microfracture treatment, published between 2013 and 2018. Titles, abstracts, and articles were reviewed, and data concerning patient demographics, study design, pre-, intra-, and postoperative findings were extracted. PRISMA guidelines were applied. The methodological quality of the included studies was analyzed by the modified Coleman Methodology Score (CMS), and aggregate data were generated.

RESULTS

Eighteen studies including 1830 defects (1759 patients) were included. Of them, 8 (59% of patients) were cohort studies without a comparison group. Overall study quality was moderate (mean total CMS: 64 points), mainly due to low patient numbers, short follow-up periods, lack of control groups and structural repair tissue evaluation, and inhomogeneity in outcome parameters. Microfracture treatment of full-thickness articular cartilage defects (3.4 ± 2.1 cm²) was performed at 43.4 ± 68.0 months of symptom duration. Postoperative assessment at 79.5 ± 27.2 months revealed failure rates of 11-27% within 5 years and 6-32% at 10 years. Imaging analysis was conducted in 10 studies, second-look arthroscopies were reported twice (n = 205 patients) and revealed well integrated fibrocartilaginous repair tissue.

CONCLUSIONS

Microfracture provides good function and pain relief at the mid-term and clinically largely satisfying results thereafter. Standardized, high-quality future study designs will better refine optimal indications for microfracture in the context of cartilage repair strategies.

LEVEL OF EVIDENCE

This systematic review is based on studies with levels of evidence ranging between I and IV (see results section and Table). Therefore, and according to this journals Instructions for Authors (SYSTEMATIC REVIEWS AND META-ANALYSES are assigned a level of evidence equivalent to the lowest level of evidence used from the manuscripts analysed), level of evidence is IV.

Carbon nanotube-based biomaterials for orthopaedic applications

Carbon nanotubes can enhance the functionality of orthopedic applications.

Infiltration and In-Tissue Polymerization of Photocross-Linked Hydrogel for Effective Fixation of Implants into Cartilage-An In Vitro Study

Effective and biocompatible fixation of implants into cartilage defects has yet to be successfully achieved. [Poly-d,l-lactic acid/polyethyleneglycol/poly-d,l-lactic acid] (PDLLA-PEG) is a chondrosupportive scaffold that is photocross-linked using the visible-light photoinitiator lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP). Interestingly, LAP and its monomer DLLA-EG are able to infiltrate the cartilage and form hydrogels upon the detection of light. After the infiltration of LAP and DLLA-EG into the implant and host cartilage, an interconnected and continuous hydrogel structure is formed which fixes the implant within the host cartilage. A mechanical test shows that the infiltrated group displays a significantly higher push-out force than the group that has not been infiltrated (the traditional fibrin fixation group). Surprisingly, the in-cartilage hydrogel also reduces the release of sulfated glycosaminoglycan from cartilage explants. However, infiltration does not affect the cell viability or the expression of cartilage marker genes. This new strategy thus represents a biocompatible and efficient method to fix implants into host tissues.

Bioactive factors for cartilage repair and regeneration: Improving delivery, retention, and activity

Articular cartilage is a remarkable tissue whose sophisticated composition and architecture allow it to withstand complex stresses within the joint. Once injured, cartilage lacks the capacity to self-repair, and injuries often progress to joint wide osteoarthritis (OA) resulting in debilitating pain and loss of mobility. Current palliative and surgical management provides short-term symptom relief, but almost always progresses to further deterioration in the long term. A number of bioactive factors, including drugs, corticosteroids, and growth factors, have been utilized in the clinic, in clinical trials, or in emerging research studies to alleviate the inflamed joint environment or to promote new cartilage tissue formation. However, these therapies remain limited in their duration and effectiveness. For this reason, current efforts are focused on improving the localization, retention, and activity of these bioactive factors. The purpose of this review is to highlight recent advances in drug delivery for the treatment of damaged or degenerated cartilage. First, we summarize material and modification techniques to improve the delivery of these factors to damaged tissue and enhance their retention and action within the joint environment. Second, we discuss recent studies using novel methods to promote new cartilage formation via biofactor delivery, that have potential for improving future long-term clinical outcomes. Lastly, we review the emerging field of orthobiologics, using delivered and endogenous cells as drug-delivering "factories" to preserve and restore joint health. Enhancing drug delivery systems can improve both restorative and regenerative treatments for damaged cartilage. STATEMENT OF SIGNIFICANCE: Articular cartilage is a remarkable and sophisticated tissue that tolerates complex stresses within the joint. When injured, cartilage cannot self-repair, and these injuries often progress to joint-wide osteoarthritis, causing patients debilitating pain and loss of mobility. Current palliative and surgical treatments only provide short-term symptomatic relief and are limited with regards to efficiency and efficacy. Bioactive factors, such as drugs and growth factors, can improve outcomes to either stabilize the degenerated environment or regenerate replacement tissue. This review highlights recent advances and novel techniques to enhance the delivery, localization, retention, and activity of these factors, providing an overview of the cartilage drug delivery field that can guide future research in restorative and regenerative treatments for damaged cartilage.

Autograft or allograft for reconstruction of anterior cruciate ligament: a health economics perspective

PURPOSE

To assess the clinical and cost-effectiveness of allografts versus autografts in the reconstruction of anterior cruciate ligaments.

METHODS

Systematic review of comparative clinical effectiveness and cost-effectiveness analysis.

RESULTS

Both autograft and allograft reconstruction are highly effective. Recent studies show little difference in failure rates between autografts and allografts (about 6% and 7%, respectively). In cost-effectiveness analysis, the price differential is the main factor, making autografts the first choice. However, there will be situations, particularly in revision ACL reconstruction, where an allograft may be preferred, or may be the only reasonable option available.

CONCLUSION

In ACL reconstruction, clinical results with autografts are as good as or slightly better than with allografts. Allografts cost more, indicating that autografts are more cost-effective and should usually be first choice.

LEVEL OF EVIDENCE

II.

Optimization of TGF-β1-transduced chondrocytes for cartilage regeneration in a 3D printed knee joint model

A cell therapy product of transforming growth factor (TGF)-β1-transduced chondrocytes has been commercialized to treat osteoarthritis of the knee via intra-articular injection. The need for arthroscopic application of the cells to simultaneously treat intra-articular pathologies of knee osteoarthritis is increasingly urgent. The purpose of this study was to optimize TGF-β1-transduced chondrocytes for arthroscopic application. The optimal composition of chondrocytes and thrombin was initially determined by measuring the consolidation time of a diverse ratio of chondrocytes and thrombin mixed with 1 ml of fibrinogen. The consolidation time of the diverse ratio of fibrinogen and atelocollagen mixed with the determined optimal ratio of chondrocytes and thrombin was evaluated. The mixture of the determined optimal ratio of TGF-β1-transduced chondrocytes, atelocollagen, fibrinogen, and thrombin was applied to the cartilage defect of the 3D printed knee joint model arthroscopically. The status of the mixture in the defect was then evaluated. Chondrogenic activities of TGF-β1-transduced chondrocytes mixed with atelocollagen were evaluated. The determined ratio of TGF-β1-transduced chondrocytes to thrombin was 8:2 and that of fibrin to atelocollagen was also 8:2. Excellent maintenance of conformation of the mixture of TGF-β1-transduced chondrocytes, atelocollagen, fibrinogen, and thrombin in the cartilage defect of the 3D printed knee joint model was observed arthroscopically. Increased chondrogenic activities were observed in the group of TGF-β1-transduced chondrocytes mixed with atelocollagen. TGF-β1-transduced chondrocytes can be applied arthroscopically to treat cartilage defects of the knee at an optimized mixing ratio of atelocollagen, fibrinogen, and thrombin.

The cost-effectiveness of osteochondral allograft transplantation in the knee

PURPOSE

Osteochondral allografts (OCA) consist of a layer of hyaline cartilage and a layer of underlying bone. They are used to repair combined defects of articular cartilage and bone. Such defects often occur in people far too young to have knee arthroplasty, for whom the main alternative to OCA is conservative symptomatic care, which will not prevent development of osteoarthritis. The aim of this report was to assess the cost-effectiveness of osteochondral allograft transplantation in the knee.

METHODS

Systematic review of evidence on clinical effectiveness and economic modelling.

RESULTS

The evidence on osteochondral allograft transplantation comes from observational studies, but often based on good quality prospective registries of all patients having such surgery. Without controlled trials, it was necessary to use historical cohorts to assess the effect of osteochondral grafts. There is good evidence that OCA are clinically effective with a high graft survival rate over 20 years. If an OCA graft fails, there is some evidence that revision with a second OCA is also effective, though less so than primary OCA. Economic modelling showed that osteochondral allograft transplantation was highly cost-effective, with costs per quality adjusted life year much lower than many other treatments considered cost effective.

CONCLUSIONS

Osteochondral allograft transplantation appears highly cost-effective though the cost per quality adjusted life year varies according to the widely varying costs of allografts. Based on one small study, revision OCA also appears very cost-effective, but more evidence is needed.

LEVEL OF EVIDENCE

II.

Priming stem cells with protein kinase C activator enhances early stem cell-chondrocyte interaction by increasing adhesion molecules

BACKGROUND

Osteoarthritis (OA) can be defined as degradation of articular cartilage of the joint, and is the most common degenerative disease. To regenerate the damaged cartilage, different experimental approaches including stem cell therapy have been tried. One of the major limitations of stem cell therapy is the poor post-transplantation survival of the stem cells. Anoikis, where insufficient matrix support and adhesion to extracellular matrix causes apoptotic cell death, is one of the main causes of the low post-transplantation survival rate of stem cells. Therefore, enhancing the initial interaction of the transplanted stem cells with chondrocytes could improve the therapeutic efficacy of stem cell therapy for OA. Previously, protein kinase C activator phorbol 12-myristate 13-acetate (PMA)-induced increase of mesenchymal stem cell adhesion via activation of focal adhesion kinase (FAK) has been reported. In the present study, we examine the effect PMA on the adipose-derived stem cells (ADSCs) adhesion and spreading to culture substrates, and further on the initial interaction between ADSC and chondrocytes.

RESULTS

PMA treatment increased the initial adhesion of ADSC to culture substrate and cellular spreading with increased expression of adhesion molecules, such as FAK, vinculin, talin, and paxillin, at both RNA and protein level. Priming of ADSC with PMA increased the number of ADSCs attached to confluent layer of cultured chondrocytes compared to that of untreated ADSCs at early time point (4 h after seeding).

CONCLUSION

Taken together, the results of this study suggest that priming ADSCs with PMA can increase the initial interaction with chondrocytes, and this proof of concept can be used to develop a non-invasive therapeutic approach for treating OA. It may also accelerate the regeneration process so that it can relieve the accompanied pain faster in OA patients. Further in vivo studies examining the therapeutic effect of PMA pretreatment of ADSCs for articular cartilage damage are required.

Repair of Damaged Articular Cartilage: Current Approaches and Future Directions

Articular hyaline cartilage is extensively hydrated, but it is neither innervated nor vascularized, and its low cell density allows only extremely limited self-renewal. Most clinical and research efforts currently focus on the restoration of cartilage damaged in connection with osteoarthritis or trauma. Here, we discuss current clinical approaches for repairing cartilage, as well as research approaches which are currently developing, and those under translation into clinical practice. We also describe potential future directions in this area, including tissue engineering based on scaffolding and/or stem cells as well as a combination of gene and cell therapy. Particular focus is placed on cell-based approaches and the potential of recently characterized chondro-progenitors; progress with induced pluripotent stem cells is also discussed. In this context, we also consider the ability of different types of stem cell to restore hyaline cartilage and the importance of mimicking the environment in vivo during cell expansion and differentiation into mature chondrocytes.

Patellofemoral Cartilage Repair

Purpose of Review

This review provides an overview of well-established and newly developed cartilage repair techniques for cartilage defects in the patellofemoral joint (PFJ). An algorithm will be presented for approaching cartilage defects considering the distinct anatomy of both the patellar and trochlear articular surfaces.

Recent Findings

Recent studies on cartilage repair in the PFJ have demonstrated improved outcomes in an attempt to delay or obviate the need for arthroplasty, and improve symptoms in young patients. While autologous chondrocyte implantation shows good and excellent outcomes for chondral lesions, osteochondral defects are adequately addressed with osteochondral allograft transplantation. In case of patellar malalignment, concomitant tibial tubercle osteotomy can significantly improve outcomes. Particulated cartilage and bone marrow aspirate concentrate are potential new alternative treatments for cartilage repair, currently in early clinical studies.

Summary

Due to the frequency of concomitant anatomic abnormalities in the PFJ, a thorough clinical examination combined with careful indication for each procedure in each individual patient combined with meticulous surgical technique is central to achieve satisfying outcomes. Additional comparative studies of cartilage repair procedures, as well as investigation of newer techniques, are needed.

Mesenchymal stem cell-derived extracellular matrix enhances chondrogenic phenotype of and cartilage formation by encapsulated chondrocytes in vitro and in vivo

Mesenchymal stem cell derived extracellular matrix (MSC-ECM) is a natural biomaterial with robust bioactivity and good biocompatibility, and has been studied as a scaffold for tissue engineering. In this investigation, we tested the applicability of using decellularized human bone marrow derived MSC-ECM (hBMSC-ECM) as a culture substrate for chondrocyte expansion in vitro, as well as a scaffold for chondrocyte-based cartilage repair. hBMSC-ECM deposited by hBMSCs cultured on tissue culture plastic (TCP) was harvested, and then subjected to a decellularization process to remove hBMSCs. Compared with chondrocytes grown on TCP, chondrocytes seeded onto hBMSC-ECM exhibited significantly increased proliferation rate, and maintained better chondrocytic phenotype than TCP group. After being expanded to the same cell number and placed in high-density micromass cultures, chondrocytes from the ECM group showed better chondrogenic differentiation profile than those from the TCP group. To test cartilage formation ability, composites of hBMSC-ECM impregnated with chondrocytes were subjected to brief trypsin treatment to allow cell-mediated contraction, and folded to form 3-dimensional chondrocyte-impregnated hBMSC-ECM (Cell/ECM constructs). Upon culture in vitro in chondrogenic medium for 21 days, robust cartilage formation was observed in the Cell/ECM constructs. Similarly prepared Cell/ECM constructs were tested in vivo by subcutaneous implantation into SCID mice. Prominent cartilage formation was observed in the implanted Cell/ECM constructs 14 days post-implantation, with higher sGAG deposition compared to controls consisting of chondrocyte cell sheets. Taken together, these findings demonstrate that hBMSC-ECM is a superior culture substrate for chondrocyte expansion and a bioactive matrix potentially applicable for cartilage regeneration in vivo.

STATEMENT OF SIGNIFICANCE

Current cell-based treatments for focal cartilage defects face challenges, including chondrocyte dedifferentiation, need for xenogenic scaffolds, and suboptimal cartilage formation. We present here a novel technique that utilizes adult stem cell-derived extracellular matrix, as a culture substrate and/or encapsulation scaffold for human adult chondrocytes, for the repair of cartilage defects. Chondrocytes cultured in stem cell-derived matrix showed higher proliferation, better chondrocytic phenotype, and improved redifferentiation ability upon in vitro culture expansion. Most importantly, 3-dimensional constructs formed from chondrocytes folded within stem cell matrix manifested excellent cartilage formation both in vitro and in vivo. These findings demonstrate the suitability of stem cell-derived extracellular matrix as a culture substrate for chondrocyte expansion as well as a candidate bioactive matrix for cartilage regeneration.

Do Outcomes of Osteochondral Allograft Transplantation Differ Based on Age and Sex? A Comparative Matched Group Analysis

BACKGROUND

The effect of patient age or sex on outcomes after osteochondral allograft transplantation (OCA) has not been assessed.

PURPOSE

To determine clinical outcomes for male and female patients aged ≥40 years undergoing OCA compared with a group of patients aged <40 years.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A review of prospectively collected data of consecutive patients who underwent OCA by a single surgeon with a minimum follow-up of 2 years was conducted. The reoperation rate, failure rate, and patient-reported outcome scores were reviewed. All outcomes were compared between patients aged <40 or ≥40 years, with subgroup analyses conducted based on patient sex. Failure was defined as revision OCA, conversion to knee arthroplasty, or gross appearance of graft failure at second-look arthroscopic surgery. Descriptive statistics, Fisher exact or chi-square testing, and Mann-Whitney U testing were performed, with P < .05 set as significant.

RESULTS

A total of 170 patients (of 212 eligible patients; 80.2% follow-up) who underwent OCA with a mean follow-up of 5.0 ± 2.7 years (range, 2.0-15.1 years) were included, with 115 patients aged <40 years (mean age, 27.6 ± 7.3 years; 58 male, 57 female) and 55 patients aged ≥40 years (mean age, 44.9 ± 4.0 years; 33 male, 22 female). There were no differences in the number of pre-OCA procedures between the groups ( P = .085). There were no differences in the reoperation rate (<40 years: 38%; ≥40 years: 36%; P = .867), time to reoperation (<40 years: 2.12 ± 1.90 years; ≥40 years: 3.43 ± 3.43 years; P = .126), or failure rate (<40 years: 13%; ≥40 years: 16%; P = .639) between the older and younger groups. Patients in both groups demonstrated significant improvement in Lysholm (both: P < .001), International Knee Documentation Committee (IKDC) (both: P < .001), Knee Injury and Osteoarthritis Outcome Score (KOOS) (both: P < .001), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) (both: P < .001), and Short Form-12 (SF-12) physical (both: P < .001) scores compared with preoperative values. Patients aged ≥40 years demonstrated significantly higher KOOS symptom ( P = .015) subscores compared with patients aged <40 years. There were no significant differences in the number of complications, outcome scores, or time to failure between the sexes. In patients aged <40 years, female patients experienced failure significantly more quickly than male patients ( P = .039). In contrast, in patients aged ≥40 years, male patients experienced failure significantly more quickly than female patients ( P = .046).

CONCLUSION

This study provides evidence that OCA is a safe and reliable treatment option for osteochondral defects in patients aged ≥40 years. Male and female patients had similar outcomes. Patients aged <40 years demonstrated lower KOOS symptom subscores postoperatively compared with older patients, potentially attributable to higher expectations of return to function postoperatively as compared with older patients.

Long-term clinical follow-up of microfracture versus mosaicplasty in articular cartilage defects of medial femoral condyle

BACKGROUND

The purpose of this study was to evaluate the outcome after cartilage repair surgery in focal defects of the knee by microfracture versus mosaicplasty.

METHODS

A cohort of 102 patients undergoing microfracture (n=52) or mosaicplasty (n=50) of a single articular cartilage defect in the medial femoral condyle of ≤50mm² was evaluated by Lysholm score before surgery, at six months, 12months, five years, 10years, and 15-18years after surgery.

RESULTS

Median age of patients at the time of surgery was 36years (range 16-58) and median follow-up time was 16years (range 14-18). Defects were treated with a median size of three square centimetres (range one to five). A significant increase was seen in the Lysholm score from mean 48 (SD 16) at baseline to 66 (SD 23; P<0.001) at the 15-18year follow-up. The Lysholm score was higher in the mosaicplasty group at six months, 12months, five years and 10years (P<0.05 for all comparisons). These differences were clinically significant at all points (>10 points). However, at the final follow-up, the difference (eight points) did not reach statistical significance.

CONCLUSIONS

In the short-term, medium-term and long-term (10years), mosaicplasty in a single cartilage defect size one to five square centimetres of the femoral condyle resulted in clinically relevant better outcome than microfracture. However, at 15-18years after the surgery such a difference could not be found. In the six month to 10-15year (after surgery) perspective, the mosaicplasty procedure offered a better outcome in this type of lesion.

LEVEL OF EVIDENCE

Level III.

Chondral tissue engineering of the reumatoid knee with collagen matrix autologous chondrocytes implant

Articular cartilage repair is still a challenge. To date evidence is insufficient to support a treatment over the others. Inflammatory conditions in the joint hamper the application of tissue engineering during chronic joint diseases. Most of the Matrix Autologous Chondrocyte Implantation (MACI) cases reported in literature do not deal with rheumatoid knees and do not have a long clinical-histologic follow-up. We report about a 46-year old woman who suffered of a painful focal Outerbridge 4th degree chondral lesion in the medial femoral condyle of her left rheumatoid knee. The tissue defect was filled by a Cartilage Regeneration System (CaReS®) based on a type I collagen matrix seeded by autologous in vitro expanded chondrocytes. The patient was followed up to ten years clinically and by MRI, and finally treated with a Total Knee Replacement for the increasing arthritis. Histologically, the explanted MACI tissue showed an increased cellularity with an extracellular matrix rich of collagen and glycosaminoglicanes even though the overall architecture was different from the normal cartilage pattern. The case reported suggests that the main goal of treatment for chondropathy is the long lasting control of symptoms, while permanent restoration of normal anatomy is still impossible. Mesenchymal stem cells, that develop into joint tissues, show immunosuppressive and anti-inflammatory qualities, in vitro and in vivo, indicating a potential role for tissue engineering approaches in the treatment of rheumatic diseases.

Chondral tissue engineering of the reumatoid knee with collagen matrix autologous chondrocytes implant

Articular cartilage repair is still a challenge. To date evidence is insufficient to support a treatment over the others. Inflammatory conditions in the joint hamper the application of tissue engineering during chronic joint diseases. Most of the Matrix Autologous Chondrocyte Implantation (MACI) cases reported in literature do not deal with rheumatoid knees and do not have a long clinical-histologic follow-up. We report about a 46-year old woman who suffered of a painful focal Outerbridge 4th degree chondral lesion in the medial femoral condyle of her left rheumatoid knee. The tissue defect was filled by a Cartilage Regeneration System (CaReS®) based on a type I collagen matrix seeded by autologous in vitro expanded chondrocytes. The patient was followed up to ten years clinically and by MRI, and finally treated with a Total Knee Replacement for the increasing arthritis. Histologically, the explanted MACI tissue showed an increased cellularity with an extracellular matrix rich of collagen and glycosaminoglicanes even though the overall architecture was different from the normal cartilage pattern. The case reported suggests that the main goal of treatment for chondropathy is the long lasting control of symptoms, while permanent restoration of normal anatomy is still impossible. Mesenchymal stem cells, that develop into joint tissues, show immunosuppressive and anti-inflammatory qualities, in vitro and in vivo, indicating a potential role for tissue engineering approaches in the treatment of rheumatic diseases.

Extracorporeal shockwave therapy vs. kinesiotherapy for osteoarthritis of the knee: A pilot randomized controlled trial

BACKGROUND

Osteoarthritis (OA) of the knee is a degenerative, painful pathology, needing conservative treatment for symptoms' relief.

OBJECTIVE

Comparing the effects of Extracorporeal shockwave therapy (ESWT) and Kinesiotherapy (KIN) on perceived health and range of motion (ROM) of the affected knee.

METHOD

A pilot randomized controlled trial with concealed allocation, assessor blinding, intention-to-treat analysis. Forty participants, aged 40-75 with OA of the knee were randomized to an ESWT and a KIN groups. The ESWT group completed 5 interventions for 5 weeks, the KIN group completed the same number of interventions. All evaluations were performed at baseline and after the treatment for: perceived health (Western Ontario and McMaster Universities questionnaire - WOMAC), range of motion (ROM).

RESULTS

After the intervention the statistical significant between groups differences favoring the ESWT were found in the WOMAC with regard to pain (p< 0.000), stiffness (p= 0.018), physical function (p< 0.000), total score (p< 0.000), extension and flexion of the affected knee (p= 0.015, p< 0.000) respectively.

CONCLUSIONS

ESWT improves WOMAC and ROM better then KIN on the affected knee in patients with OA of the knee.

Treatment of Knee Osteochondral Lesions Using a Novel Clot of Autologous Plasma Rich in Growth Factors Mixed with Healthy Hyaline Cartilage Chips and Intra-Articular Injection of PRGF

Knee cartilage or osteochondral lesions are common and challenging injuries. To date, most symptomatic lesions warrant surgical treatment. We present two cases of patients with knee osteochondral defects treated with a one-step surgical procedure consisting of an autologous-based matrix composed of healthy hyaline cartilage chips, mixed plasma poor-rich in platelets clot, and plasma rich in growth factors (PRGF). Both patients returned to playing soccer at the preinjury activity level and demonstrated excellent defect filling in both magnetic resonance imaging and second-look arthroscopy (in one of them). The use of a clot of autologous plasma poor in platelets with healthy hyaline cartilage chips and intra-articular injection of plasma rich in platelets is an effective, easy, and cheap option to treat knee cartilage injuries in young and athletic patients.

Joint Preservation Techniques in Orthopaedic Surgery

CONTEXT

With increasing life expectancy, there is growing demand for preservation of native articular cartilage to delay joint arthroplasties, especially in younger, active patients. Damage to the hyaline cartilage of a joint has a limited intrinsic capacity to heal. This can lead to accelerated degeneration of the joint and early-onset osteoarthritis. Treatment in the past was limited, however, and surgical treatment options continue to evolve that may allow restoration of the natural biology of the articular cartilage. This article reviews the most current literature with regard to indications, techniques, and outcomes of these restorative procedures.

EVIDENCE ACQUISITION

MEDLINE and PubMed searches relevant to the topic were performed for articles published between 1995 and 2016. Older articles were used for historical reference. This paper places emphasis on evidence published within the past 5 years.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

Autologous chondrocyte implantation and osteochondral allografts (OCAs) for the treatment of articular cartilage injury allow restoration of hyaline cartilage to the joint surface, which is advantageous over options such as microfracture, which heal with less favorable fibrocartilage. Studies show that these techniques are useful for larger chondral defects where there is no alternative. Additionally, meniscal transplantation can be a valuable isolated or adjunctive procedure to prolong the health of the articular surface.

CONCLUSION

Newer techniques such as autologous chondrocyte implantation and OCAs may safely produce encouraging outcomes in joint preservation.

Cartilage repair in the degenerative ageing knee

Background and purpose - Cartilage damage can develop due to trauma, resulting in focal chondral or osteochondral defects, or as more diffuse loss of cartilage in a generalized organ disease such as osteoarthritis. A loss of cartilage function and quality is also seen with increasing age. There is a spectrum of diseases ranging from focal cartilage defects with healthy surrounding cartilage to focal lesions in degenerative cartilage, to multiple and diffuse lesions in osteoarthritic cartilage. At the recent Aarhus Regenerative Orthopaedics Symposium (AROS) 2015, regenerative challenges in an ageing population were discussed by clinicians and basic scientists. A group of clinicians was given the task of discussing the role of tissue engineering in the treatment of degenerative cartilage lesions in ageing patients. We present the outcomes of our discussions on current treatment options for such lesions, with particular emphasis on different biological repair techniques and their supporting level of evidence. Results and interpretation - Based on the studies on treatment of degenerative lesions and early OA, there is low-level evidence to suggest that cartilage repair is a possible treatment for such lesions, but there are conflicting results regarding the effect of advanced age on the outcome. We concluded that further improvements are needed for direct repair of focal, purely traumatic defects before we can routinely use such repair techniques for the more challenging degenerative lesions. Furthermore, we need to identify trigger mechanisms that start generalized loss of cartilage matrix, and induce subchondral bone changes and concomitant synovial pathology, to maximize our treatment methods for biological repair in degenerative ageing joints.

Surgical interventions (microfracture, drilling, mosaicplasty, and allograft transplantation) for treating isolated cartilage defects of the knee in adults

BACKGROUND

Cartilage defects of the knee are often debilitating and predispose to osteoarthritis. Microfracture, drilling, mosaicplasty, and allograft transplantation are four surgical treatment options that are increasingly performed worldwide. We set out to examine the relative effects of these different methods.

OBJECTIVES

To assess the relative effects (benefits and harms) of different surgical interventions (microfracture, drilling, mosaicplasty, and allograft transplantation) for treating isolated cartilage defects of the knee in adults.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register, CENTRAL, EMBASE, MEDLINE, SPORTDiscus, LILACS, trial registers and conference proceedings up to February 2016.

SELECTION CRITERIA

Any randomised or quasi-randomised trials that evaluated surgical interventions (microfracture, drilling, mosaicplasty, and allograft transplantation) for treating isolated cartilage defects of the knee in adults.

DATA COLLECTION AND ANALYSIS

At least two review authors independently selected studies, assessed risk of bias and extracted data. Intervention effects were assessed using risk ratios (RR) for dichotomous data and mean differences (MD) for continuous data, with 95% confidence intervals (CI). Data were pooled using the fixed-effect model, where possible.

MAIN RESULTS

We included three randomised controlled trials comparing mosaicplasty versus microfracture for isolated cartilage defects in adults. Two trials were single-centre trials and one involved three centres. These small trials reported results for a total of 133 participants, of whom 79 (59%) were male. Mean participant age in the three trials ranged from 24.4 years to 32.3 years. All studies included grade 3 or 4 cartilage lesions (International Cartilage Repair Society (ICRS) classification). The defect area ranged from 1.0 cm² to 6.0 cm²; the mean area in all three trials was 2.8 cm². No trials of allograft transplantation or drilling were identified.All trials were judged as being at high or unclear risk of performance and reporting bias. We judged that the quality of evidence was very low for all outcomes. For individual outcomes, we downgraded the quality of evidence by one or two levels for risk of bias, one level for indirectness where there were data from a single-centre trial only, one or two levels for imprecision where there were wide confidence intervals and an insufficient number of events, and one level for inconsistency reflecting heterogeneity. This means that we are very uncertain about the estimates for all outcomes.There is very low quality evidence from one single-centre trial (57 participants), which included athletes only, that mosaicplasty resulted in higher patient-reported function scores (probably the IKDC 2000 subjective knee evaluation score) compared with microfracture (range 0 to 100; higher score = better function) at one year follow-up (MD 10.29 favouring mosaicplasty, 95% CI 7.87 to 12.71). Very low quality evidence from the same trial showed that this effect persisted in the long term at 10 years follow-up. However, there is very low quality evidence from the two other trials (72 participants) of little difference in patient-reported function, assessed via the Lysholm score (range 0 to 100; higher score = better function), between the two groups at long-term follow-up (MD -1.10 favouring microfracture, 95% CI -4.54 to 2.33). One trial (25 participants) provided very low quality evidence of no significant difference between the two groups in quality of life or pain at long-term follow-up. Pooled results for treatment failure - primarily symptom recurrence - reported at long-term follow-up (means ranging from 6.3 to 1.4 years) in the three trials (129 participants) favoured mosaicplasty (10/64 versus 20/65; RR 0.47, 95% CI 0.24 to 0.90). Based on an illustrative risk of 379 treatment failures per 1000 patients treated with microfracture, there is very low quality evidence that 201 fewer patients (95% CI 38 to 288 fewer) would have treatment failure after mosaicplasty. All three trials reported activity scores but due to clear statistical and clinical heterogeneity, we did not pool the long term Tegner score results. There was very low quality evidence from one study (57 participants) of higher Tegner scores - indicating greater activity - at intermediate-term and long-term follow-up in the mosaicplasty group; however, the between-group difference may not be clinically important. The other two trials provided very low quality evidence of no significant difference between the two groups in activity scores.

AUTHORS' CONCLUSIONS

We found no evidence from randomised controlled trials on allograft transplantation or drilling. The very low quality evidence from RCTs comparing mosaicplasty with microfracture is insufficient to draw conclusions on the relative effects of these two interventions for treating isolated cartilage defects of the knee in adults. Of note is that treatment failure, with recurrence of symptoms, occurred with both procedures. Further research is needed to define the best surgical option for treating isolated cartilage defects. We suggest the greatest need is for multi-centre RCTs comparing reconstructive procedures (mosaicplasty versus allograft transplantation) for large osteochondral lesions and reparative procedures (microfracture versus drilling) for small chondral lesions.